This invention relates to shock absorber, and more particularly, the invention relates to a twin tube shock absorber having adaptive damping control.
Shock absorber dampers are used to dampen suspension movement by absorbing the energy of the impacts transmitted from the roadway and dissipating it as heat. Typically, dampers have a fixed set of valves, and the force generated by the damper is simply a function of the speed at which the damper is moving. As a result, each damper is designed with a particular speed in mind.
One type of damper is a twin tube arrangement in which a working cylinder is surrounded by a reservoir. A piston moves through fluid in the working cylinder and forces the fluid through a series of valves or ports, which acts to impede the motion of the piston and dampen the input from the roadway. The fluid passes through valves in a cylinder head and compression head into the reservoir during the compression stroke to accommodate the volume of a piston rod, which compresses a gas cell located in the reservoir. During the recoil stroke, the fluid exits the reservoir through other valves to the working cylinder through another set of valves. Unfortunately, these valves are only able to provide dampening that is a function of the piston speed.
It is desirable to provide a stiffer damper as the piston speed increases. The prior art has achieved this by incorporating sensors that monitor piston speed and a power supply that actuates valves to regulate the flow of fluid and adjust damping. However, these systems are complex and costly. Therefore, it is desirable to provide adjustable or adaptive dampening without external sensor power.